Method of making sliders for slide fasteners



Dea 8, 1942.

. G. DAHLIN 2,304,340

METHOD oF 4MAxlNG SLIDERS FOR SLIDE FAST'ENERS Filed NOV. 16, 1959 p7 ////////////////f//m y 'z3 ff' s /f/M Inventor 5 I I 7 gj%ln Pnemed'nec. s, 1942 2,304,340 FICE METHOD F MAKING SLIDERS FOR SLIDE FASTENERS Gusta! Dahlin, St. Catharines, Ontario, Canada, assignor to Lightning'Fastener Company, Limited, St. Catharines, Ontario, Canada Application November 16, 1939, Serial No.

Canada September 29, 1939 Claims.

The invention relates to improvements in sliders for slide fasteners of the type comprising a pair of flexible tapes carrying spaced interlocking clements along one edge of each which areadapted to be engaged and disengaged by the movement of a'slid'er tberealong, and in particular to a slider for such a fastener which is made by casting or moulding.

An object of the invention is to devise a novel method o f securing to the slider body the track, which may serve merely as a means for connecting a pull member to the body or, additionally, as means for locking the slider on the interlocking elements at any desired point over the length of the fastener.

A further object is to provide such a slider which may be assembled during manufacture very readily and with a minimum number of operations.

An additional object is to produce a lock slider which is readily susceptible to manufacture from nonmetallic material such as a plastic and which is much stronger and much less liable to become inoperative due to careless handling, washing in hot water, or the like, than previously known plastic lock sliders. 4

i With the above and other objects, which will hereinafter become apparent as the specification proceeds, in View my invention consists, in a preferred embodiment, of the construction and arrangement all ashereinafter more particularly described and illustrated with companying drawing in which:

Fig. 1 is a fragmentary plan view of a' slide fastener employing my improved slider;

Fig. 2 is an enlarged sectional view through the slider of Fig. 1 taken on the line 2, 2 of Fig. 1 and showing the slider in the locked position;

reference to the acvAs, illustrated Ain Fig. 1, the orthodox slide fastener on which my slider may be`used com.- prises a pair of flexible supporting members, such as tapes I. each of which is provided with a plurality of interlocking lelements 2 along one edge, over which the slider travels for opening and closing of the fastener.

The slider of the invention consists of upper and lower wings 3 and 4 connected by a diamond, or neck, 5 which denne channels for the passage of the interlocking elements 2; a pull member 6 is connected to the slider by a track 1 which, as shown in Figs. 2 to 8, inclusive, also acts as means for'locking the slider at any desired point along the length of the fastener. In accordance with the invention, the track 1 is fabricated first and then the body of the slider. is cast in fluid form around the extremities of the track so that, after solidication of the body material, the track is rmly secured to the slider body.

. l have found that when using any of the materials commonly employed in casting objects such as a slide fastener slider, i. e. zinc base or aluminum alloys representing the metals, or cellulose acetate representing the plastic materials, it is practically impossible to bond cast material to a second'material which may either be the same as, or different from,'the casting material, so long as the second material is exposed to the first material in the solid state.` That is to say, it is possible to cast an object such as the track 1 in one moulding operation and then cast a second object such as the y slider body around it without developing any sub- Fig. 3 is a View correspondingto Fig. 2'b ut Y showing the slider in the unlocked position;

Fig.v 4 is a side elevational view of a precast track used in the slider f Fig. 5 is a plan view of the parting. surface of one-half of a mould which may be used to castv my improved slider showing retractable core members in longitudinal section;

Fig. 6 is a view corresponding to Fig. 5 showing the track of Fig. 4 insert;

Fig. 7 is a viewcorresponding to Fig. 5 after the slider body has been cast in the die section and showing the body in longitudinal section;

Fig. 8 is a longitudinal sectional view' of the finished slider removed from the die section and illustrating the method of withdrawing one of the cores therefrom; and r Fig. 9 is a longitudinal sectional view, through a non-locking slider also constructed according to the invention.

Like characters of reference designate corresponding parts in the different figures.

placed in the die cavity as an Isame observation applies if the first article.

stantial bond between the The such as the track, is made by stamping or machining. The extremity 8 of the track i is, therefore, headed, which, in effect, keys the extremity into the slider body and secures it firmly thereon.

I have made use of the above discussed property of cast materials in producing the lock slider shown without the necessity of complicated assembly operations. By making the extremity 9 of the track 'I headed and protecting the lower vsurtwo cast pieces.

' face of the lower extremity 9 from contact with the moulding material of the body when casting the body therearoun-d, the extremity 9 of .the track in the finished slider may be depressed inwardly of the slider wing 3, but is prevented from being4 pulled outwardly of the wing by the engagement of the tapering surfaces of the head with the surfaces of the wing 3 which are moulded therearound during casting of the slider body. If, then, the track 'l is given the normally bent shape shown in Fig. 4 and is cast into the slider body while straightened out, as shown in Fig. 3,

the track, when released from the conningstress the position shown in Fig. 2'

of the die will assume with the extremity 9 the slider channel.

of the track lying Within Then by providing the locksuch as upsetting,

ing projection 'i0 on the extremity Q of the track which projects within vthe slider channels, such projection normally engages the interlocking elements 2 of the fastener to prevent movement of the slider therealong as illustrated in Fig. 2 and may be withdrawn from Aengagement with the interlocking elements on lifting ythe free extremity of the track by means of the pull 6, as shown in Fig. 3.

In order to provide increased resiliency in the track l, particularly when it is cast from lmetal, .I may provide a spring member Il cast into the track. This may be included easily by setting up the spring member as an insert in the die in which the track is cast, the portion I2 of the Ispring being held in a socket in the die for supporting the spring centrally of the vtrack and later serving as additional anchorage means for the track in the slider body.

Figs. 5 to 8 inclusive will illustrate one type of die for casting my improved slider. Such a die might consist of two sections, only one of which, indicated by the numeral i3, is shown. Each' die section is provided with 4a cavity I@ which encloses the track member l, and a cavity I5 which forms the body of the slider, the Y- shaped channels being formed by a single re-v tractable core It and a second retractable core split into two parts Ii and i8. It will be noted that the core part I8 is provided with a hollow i boss i9.

To use the diethe track l, which has been pre-fabricated in th'e form shown in Fig. i, is pressed into the cavity It of the die section i3. which necessitates the track being straightened out to assume the position indicated inv Fig. 6, with the projections Ill of the headed extremity 9 of the track being enclosed in the hollow 2@ of the boss I9 when the cores I6 and the parts il and it are in the innermost or protracted position. The corresponding section of the die (not shown) is then closed onto the die section i3 and the body is cast between the two sections, as indicated in Fig. 7.. On opening the die sections and removing the core It the finished slider may be removed from the die sections with the core parts I1 and I3 still retained in the slider channel. By first withdrawing the corepart i1, and then dropping the part I8 into the space left thereby, the part I8 may be withdrawn without interference by the locking projection I0 on the track, as indicated in Fig. 8. Since `the material of the slider body does not adhere to the material of the track, the free extremity 9 of the 'track is .then permitted to iiex inwardly of thev slider body, which restores the track to its normal shape as shown in Fig. 4.

As shown in Fig. 9, the same method of construction may be used to fabricate a non-locking slider, in which case a track 2| provided with headed extremities 22 and 23 may be cast into the upper wing 24 of the slider with both extremities of the track being solidly Janchored.

It should be obvious from the foregoing that a slider constructed according to the invention may be very readily and cheaply fabricated, Asince both the track and the body may be cast by orthodox methods and the track may be assembled in operative position in the slider body during the casting of the body without the necessity of time-consuming securing methods,

clinching, welding, soldering, or'the like, and also that since the track is held rigidly secured in the body during an ordinary casting operation accurate machining operations or other means of securing close tolerance between the working parts of the slider are elimi nated.

While `i have shown and described in this application two embodiments which my invention may assume in practice, it will be understood that such disclosure is merely for the purpose of illustration and description, and that various other forms may be devised within the scope of my invention as dened in the appended claims.

What I claim as my invention is: y

1; The method 'of making a lock slider for a slide fastener of the class described which comprises assembling a resiliently deformable track in a mould as an insert, and casting the slider body in said mould to rigidly anchor a part of said track in saidfbody and to loosely retain another part of said track in said body to` anchor another part of said track against disengagement from said body and to permit flexing of the track withvrespect to the body on removal of the finished slider from the mould.

2. The method of making a lock slider for a slide fastener of the class described which comprises assembling a, resiliently deformable track having headed extremities in a mould as an insert with the headed extremities ofl the track projecting into the mould cavity, positioning a. core in said mould in contact with one headed extremity of the track, and casting the. slider body in the mould to anchor one extremity of the track in the body and to permit exing of the other extremity of the track inwardly of the slider on removal of the finished slider from the mould.

3. The method of fabricating a structure including a first element having a non-uniform section movably retained in a, cavity in a second element by engagement of at least part of the wall of said cavity with a portion of said first element having a reduced section which comprises assembling said first element in a. mould as an insert, casting said second element in the mould around said insert, and loosening vany grip of said second element on said first element to leave the first element movably retained in the second element. p

4. The method f fabricating a structure including a rst element having a non-uniform section movably retained in a. cavity in a second element by engagement of at least part of the 555wall of said 'cavity with a portion of said rst element having a reduced section which comprises casting said rst element in a first mould,

assembling such casting as an insert in a second mould, casting said second element in the mould around said insert, and loosening any grip of said second element on said first element to leave the firstelement movably retained in the second element.

5. The method of making a lock slider for a slide fastener 'of the class described which comprises assembling a resiliently deformable track in a mould as an insert and casting the slider body in said mould to rigidly anchor a part of said track in said body and to retain another part of said' track against disengagement from said body and to permit flexing of s'aid last mentioned part of the track with respect/to the body,

on removal of the nished slider from the mould.

GUSTAF DAmiIN. 

